Volkmar Hartje

Downscaling nonclimatic drivers for surface water vulnerabilities in the Elbe river basin

Aggregated consideration of both climate and socio-economic change in a coarse spatial resolution is a central feature for scenario development in global change research. Downscaling of the supposed aggregated changes is a necessary prerequisite for the assessments of global change at the regional scale. The present paper describes the method and results of an approach to develop and to apply scenarios of socio-economic change at a sub-national level, which are consistent with global change scenarios. National and regional models of economic and demographic development are used to regionalise drivers of socio-economic change. Scenario results are subsequently applied in order to analyse the impacts of socio-economic and climatic changes on water management issues in the Elbe river basin. Starting from global IPCC-Emissions Scenarios and taking up their key points, we formulate two scenarios for the German and Czech parts of the Elbe catchment areas. We present a system of demographic and economic models, designed to consistently project socio-economic developments at a national and sub-national level and, thus, to quantitatively illustrate our scenarios. The results show that in a scenario that assumes continued globalisation and emphasis on economic growth, export orientation will result in a comparatively high share of manufacturing. Growth spreads from centres to peripheral regions. Still, at the national level, the increase in population and employment will be modest and create little additional pressure, but water stress will be considerably stronger on a regional basis, namely in metropolitan areas such as Prague, Berlin and Hamburg. In a scenario where economic goals are balanced with ecologic and social ones, growth is weaker and the weight of the service sector increases more rapidly, thus easing the driving forces for overall water demand and pollution. However, as in this scenario regional metropolitan centres develop at the cost of peripheral regions, regional development is more selective and the driving forces for potential water stress will diverge spatially.

Kosten einer möglichen Klimaänderung auf Sylt

Kustenraume gelten als besonders betroffen von den Folgen eines moglichen Klimawandels. Entsprechend war es Ziel des Projektes, die dadurch entstehenden Kosten exemplarisch am Beispiel der Insel Sylt zu ermitteln. Bewertet wurden im Wesentlichen zwei Auswirkungen auf die Insel Sylt: Erstens die Erosion auf der Westseite der Insel, die zu Vermogensschaden aufgrund der Verluste von Gebauden, Infrastruktur und Grundstucken fuhren kann. Zweitens die Beeintrachtigung von Natur und Landschaft in Form eines Verlustes seltener Wattenmeerbiotope als Folge starkeren Kustenschutzes auf der Ostseite. Fazit der okonomischen Bewertung ist, dass der Klimawandel entsprechend der hier untersuchten Variante durch zusatzliche Sandvorspulun- gen beherrschbar ist und daher keine dramatischen Entwicklungen erwarten lasst. Die Nutzen aus verstarkten Kustenschutzmasnahmen ubersteigen die Kosten fur die zusatzlichen Sandvorspu- lungen um ein Vielfaches. Und die Kosten fur auf der Ostseite zu prufende alternative Kusten- schutzmassnahmen waren durch die Nachfrage nach dem Schutz des Wattenmeeres als Natur- landschaft vor den Folgen des Klimawandels ebenfalls deutlich gedeckt.

Take your swimsuit along: the value of improving urban bathing sites in the metropolitan area of Berlin

Many inhabitants of Berlin enjoy bathing in lakes and rivers during the summer. However, so far no data exist about who goes bathing and what quality bathers expect from bathing sites. In an online survey conducted during the summer of 2007 respondents were presented with a choice experiment concerning various attributes of bathing sites such as water quality or cleanliness of the beach. Applying both random parameter logit models as well as a latent class model reveals that unobserved taste heterogeneity is present among bathers, i.e. not all bathers would benefit equally from improving bathing sites. A test concerning preference consistency reveals high internal validity.

The legacy of large dams and their effects on the water-land nexus

Man-made river dams and reservoirs have increasingly been constructed to modify free-flowing rivers to benefit society through hydropower generation, irrigation, and other water supplies, navigation, and flood prevention. However, this ongoing global boom (Zarfl et al. 2015) also triggers harmful outcomes to local, directly affected stakeholder groups, and the environment. Particularly, profound social impacts of involuntary resettlement need alleviatingmeasures and room for remembrance. Restoring vital characteristics of aquatic ecosystems after artificial reservoir establishment, to any possible degree, may contribute to higher welfare and sustainability. Large reservoirs cause both particularly large positive and negative effects on society, the economy, and the environment. In Brazil, reservoirs were initially constructed for the primary purpose of hydroelectricity generation, to prevent flooding, and to provide irrigation capacities in the dryer parts of the country. However, an increasing number of users and usages have increased the pressure on stored and flowing water. Their requirements differ in terms of river discharge, water quality, and reservoir levels, most often reducing the options of the water users downstream. The resolution of conflicts over water allocation and management has been legally supported by the Brazilian Water Act since 1997, which introduced the paradigm of multiple and equally important water uses. Several of these water uses are closely linked to land-use practices, particularly irrigated agriculture. By law, domestic supply for the river basin’s residents sets a priority for water consumption during pronounced water scarcity. In terms of accessibility and water quality, water abstraction for domestic supply is being affected by water levels. Domestic water supply is also directly linked to water pollution through dilution of untreated wastewater in the river or reservoir. The intertwined and often divergent necessities and externalities of water and land use call for a coordinated management and governance approach to mitigate conflicts. Yet many of